the _________ function can return a specified number of characters beginning at any position within a string.the _________ function can return a specified number of characters beginning at any position within a string.the _________ function can return a specified number of characters beginning at any position within a string.the _________ function can return a specified number of characters beginning at any position within a string.the _________ function can return a specified number of characters beginning at any position within a string.the _________ function can return a specified number of characters beginning at any position within a string.the _________ function can return a specified number of characters beginning at any position within a string.the _________ function can return a specified number of characters beginning at any position within a string.